Can a 2.00 intake valve be used on a 5.3 cylinder head?
01-26-2012, 10:04 PM
#41
TECH Enthusiast
iTrader: (5)
Join Date: Jan 2010
Location: Huntsville, Alabama - SA, TX is home
Posts: 676
Likes: 0
Received 1 Like
on
1 Post
Really guys? Talk about misinformation....
First of all, 10 HP from stock 5.3 heads? Seriously? Remind me again why they are so much cheaper than ls1 heads?
2nd, the cylinder bore is only part of the equation when it comes to shrouded valves. The 5.3 combustion chamber is smaller in diameter to match the smaller bore of the 5.3 block, when you put a valve that is larger it puts it closer to the wall of the chamber, shrouding the valve. In order to take full advantage of the larger valve, it needs to be un shrouded.
First of all, 10 HP from stock 5.3 heads? Seriously? Remind me again why they are so much cheaper than ls1 heads?
2nd, the cylinder bore is only part of the equation when it comes to shrouded valves. The 5.3 combustion chamber is smaller in diameter to match the smaller bore of the 5.3 block, when you put a valve that is larger it puts it closer to the wall of the chamber, shrouding the valve. In order to take full advantage of the larger valve, it needs to be un shrouded.
5.3 are not cheaper. I pay $100 for both 5.3 and LS1 heads used. The lack of demand for them can be from not knowing their capability. Everyone was focused on the flow results and power gains of the 243 cast head and thats what all wanted. But if a 862 head can be made to flow or even outflow the 243 then that'd be my pick for the compression without paying for milling. Its the most cost effective way if able to port yourself.
Haven't you ever wondered why PRC 5.3 heads have been so popular?
And on the shrouding of the valve I think I covered that and how to adjust it.
Last edited by AGearHead4Life; 01-26-2012 at 10:53 PM.
01-26-2012, 10:12 PM
#42
Really guys? Talk about misinformation....
First of all, 10 HP from stock 5.3 heads? Seriously? Remind me again why they are so much cheaper than ls1 heads?
2nd, the cylinder bore is only part of the equation when it comes to shrouded valves. The 5.3 combustion chamber is smaller in diameter to match the smaller bore of the 5.3 block, when you put a valve that is larger it puts it closer to the wall of the chamber, shrouding the valve. In order to take full advantage of the larger valve, it needs to be un shrouded.
First of all, 10 HP from stock 5.3 heads? Seriously? Remind me again why they are so much cheaper than ls1 heads?
2nd, the cylinder bore is only part of the equation when it comes to shrouded valves. The 5.3 combustion chamber is smaller in diameter to match the smaller bore of the 5.3 block, when you put a valve that is larger it puts it closer to the wall of the chamber, shrouding the valve. In order to take full advantage of the larger valve, it needs to be un shrouded.
Someone correct me if I am wrong, but I am almost sure that valve shrouding is only a problem when you put say a 317 head on a 4.8 or a 5.3 not a 5.3 head on a larger bore like a 5.7 LS1. Am I totally wrong here?
And also if a Stock LS1 uses a 2.0 intake valve please tell me how a 2.0 intake valve on a 5.3 head will shroud the valve!!! It's the valve and it's relation to the piston and what can fit over that piston equally without overlapping the outside diameter of the piston. That's why when you notch valve reliefs into a piston and then want to run a larger intake valve you have to re notch the piston again.
Last edited by Fbodyjunkie06; 01-26-2012 at 10:18 PM.
01-26-2012, 10:14 PM
#43
TECH Enthusiast
iTrader: (5)
Join Date: Jan 2010
Location: Huntsville, Alabama - SA, TX is home
Posts: 676
Likes: 0
Received 1 Like
on
1 Post
Because the 5.3 motors were made in PROLIFIC quantities compared to LS1's that's why.
Someone correct me if I am wrong, but I am almost sure that valve shrouding is only a problem when you put say a 317 head on a 4.8 or a 5.3 not a 5.3 head on a larger bore like a 5.7 LS1. Am I totally wrong here?
And also if a Stock LS1 uses a 2.0 intake valve please tell me how a 2.0 intake valve on a 5.3 head will shroud the valve!!!
Someone correct me if I am wrong, but I am almost sure that valve shrouding is only a problem when you put say a 317 head on a 4.8 or a 5.3 not a 5.3 head on a larger bore like a 5.7 LS1. Am I totally wrong here?
And also if a Stock LS1 uses a 2.0 intake valve please tell me how a 2.0 intake valve on a 5.3 head will shroud the valve!!!
On the shrouding, the valve can be shrouded by the side of the combustion chamber nearest the valve. Standby for photo.
01-26-2012, 10:27 PM
#45
TECH Enthusiast
iTrader: (5)
Join Date: Jan 2010
Location: Huntsville, Alabama - SA, TX is home
Posts: 676
Likes: 0
Received 1 Like
on
1 Post
Here's a photo of where the shrouding issue can be in the CC of the head. Areas boxed. The valve can be too close to the wall. Even more at higher lift it appears.
01-26-2012, 10:31 PM
#46
01-26-2012, 10:34 PM
#47
TECH Enthusiast
iTrader: (5)
Join Date: Jan 2010
Location: Huntsville, Alabama - SA, TX is home
Posts: 676
Likes: 0
Received 1 Like
on
1 Post
Someone correct me if I am wrong, but I am almost sure that valve shrouding is only a problem when you put say a 317 head on a 4.8 or a 5.3 not a 5.3 head on a larger bore like a 5.7 LS1. Am I totally wrong here?
And also if a Stock LS1 uses a 2.0 intake valve please tell me how a 2.0 intake valve on a 5.3 head will shroud the valve!!! It's the valve and it's relation to the piston and what can fit over that piston equally without overlapping the outside diameter of the piston. That's why when you notch valve reliefs into a piston and then want to run a larger intake valve you have to re notch the piston again.
And also if a Stock LS1 uses a 2.0 intake valve please tell me how a 2.0 intake valve on a 5.3 head will shroud the valve!!! It's the valve and it's relation to the piston and what can fit over that piston equally without overlapping the outside diameter of the piston. That's why when you notch valve reliefs into a piston and then want to run a larger intake valve you have to re notch the piston again.
01-26-2012, 11:18 PM
#49
Well I was trying to relate how the valve sits above the piston and how the two have to be equal in size so that they fit correctly. Now that I think about it I can't really find a way to put it in words to fully explain what I was trying to correlate PTV and Valve Shrouding. I guess the point I was making is if the valve was bigger than intended for the bore that it wouldn't sit in that notch that had been made for it correctly kinda like how it wouldn't sit above the piston correctly is what I was trying to say.
01-26-2012, 11:22 PM
#50
Your picture you posted is what I was trying to state actually. Were you have it boxed and saying it's too close to the cc, that part of the cc seals with the bore and if the valve was bigger than that it would hit that part of the chamber or bore just like you have shown in the picture.
01-26-2012, 11:24 PM
#51
2nd, the cylinder bore is only part of the equation when it comes to shrouded valves. The 5.3 combustion chamber is smaller in diameter to match the smaller bore of the 5.3 block, when you put a valve that is larger it puts it closer to the wall of the chamber, shrouding the valve. In order to take full advantage of the larger valve, it needs to be un shrouded.
JK with ya man, no hard feelings alright?
01-26-2012, 11:36 PM
#52
TECH Enthusiast
iTrader: (5)
Join Date: Jan 2010
Location: Huntsville, Alabama - SA, TX is home
Posts: 676
Likes: 0
Received 1 Like
on
1 Post
Read: http://www.smokemup.com/tech/ls1.php
They show 5.3 and LS1 heads have nearly identical flow rates. Ask others. They'll tell you. They have the same ports.
01-26-2012, 11:55 PM
#54
TECH Enthusiast
iTrader: (5)
Join Date: Jan 2010
Location: Huntsville, Alabama - SA, TX is home
Posts: 676
Likes: 0
Received 1 Like
on
1 Post
so you already have 5.3 heads???
Or do you already have ls1 heads? or both? make up my mind...
so you dont have 5.3 heads???
so I'm back to asking what your trying to accomplish err...what you already have...I'm not sure...and you say I need to edit my posts?
so let me get this straight...
you have LS1 heads that flow good and already have 2.0 intake valves and unshrouded valves.
you want to BUY a set of 5.3 heads, PAY for a valve job for 2.0 intake valves, then port the heads and chambers to make them work just to raise your compression?
but....you already have LS1 heads that
1. already have unshrouded 2.00 intake valves
and
2. just need ported to your liking...
and
3. need milled to get the same compression ratio your going to get with 5.3 heads, all with unshrouded valves...
or do you not have the LS1 heads....I'm not sure after "re-reading" the thread. either way you stack it, what your wanting to do does not make any sense unless you already have the 5.3 heads and dont have LS1 heads like you stated. I just dont get why you want to buy and inferior head and put more money in it to make it what you want when you have what you want right in front of you with most of the work done already.
sorry, I'm not editing my posts.
Or do you already have ls1 heads? or both? make up my mind...
so you dont have 5.3 heads???
so I'm back to asking what your trying to accomplish err...what you already have...I'm not sure...and you say I need to edit my posts?
so let me get this straight...
you have LS1 heads that flow good and already have 2.0 intake valves and unshrouded valves.
you want to BUY a set of 5.3 heads, PAY for a valve job for 2.0 intake valves, then port the heads and chambers to make them work just to raise your compression?
but....you already have LS1 heads that
1. already have unshrouded 2.00 intake valves
and
2. just need ported to your liking...
and
3. need milled to get the same compression ratio your going to get with 5.3 heads, all with unshrouded valves...
or do you not have the LS1 heads....I'm not sure after "re-reading" the thread. either way you stack it, what your wanting to do does not make any sense unless you already have the 5.3 heads and dont have LS1 heads like you stated. I just dont get why you want to buy and inferior head and put more money in it to make it what you want when you have what you want right in front of you with most of the work done already.
sorry, I'm not editing my posts.
You should do as requested and remove your posts confusing the thread. Once that is done I'll be able to go back and remove mine that are only here to deal with you.
01-27-2012, 12:12 AM
#55
I stand corrected on the original valve size of the 5.3 heads, as you can see I never argued that.
As far as my other posts, they will stay. The ports on the 5.3 heads may be the same but with the stock valve sizing of the 5.3 heads, they will not flow the same. Velocity may be a tad higher given the smaller valve and given the same volume of the cylinder, but putting a stock 5.3 head up against a stock ls1 head and claiming 10 HP from .6 increase in compression ratio is nonsense. If that was the case, everyone would have stock 5.3 heads on their cars.
After the installation of the larger valves in the 5.3 head, you basically have a stock milled ls1 head.
Call any machine shop and compare prices to install larger valves and just having them milled.
Which brings me back to my original point that buying 5.3 heads for an increase in power is pointless when you already have ls1 heads. Period.
Now, I'm not trying to rudely correct you, however, I do know what I am talking about.
As far as my other posts, they will stay. The ports on the 5.3 heads may be the same but with the stock valve sizing of the 5.3 heads, they will not flow the same. Velocity may be a tad higher given the smaller valve and given the same volume of the cylinder, but putting a stock 5.3 head up against a stock ls1 head and claiming 10 HP from .6 increase in compression ratio is nonsense. If that was the case, everyone would have stock 5.3 heads on their cars.
After the installation of the larger valves in the 5.3 head, you basically have a stock milled ls1 head.
Call any machine shop and compare prices to install larger valves and just having them milled.
Which brings me back to my original point that buying 5.3 heads for an increase in power is pointless when you already have ls1 heads. Period.
Now, I'm not trying to rudely correct you, however, I do know what I am talking about.
01-27-2012, 01:22 AM
#56
I stand corrected on the original valve size of the 5.3 heads, as you can see I never argued that.
As far as my other posts, they will stay. The ports on the 5.3 heads may be the same but with the stock valve sizing of the 5.3 heads, they will not flow the same. Velocity may be a tad higher given the smaller valve and given the same volume of the cylinder, but putting a stock 5.3 head up against a stock ls1 head and claiming 10 HP from .6 increase in compression ratio is nonsense. If that was the case, everyone would have stock 5.3 heads on their cars.
After the installation of the larger valves in the 5.3 head, you basically have a stock milled ls1 head.
Call any machine shop and compare prices to install larger valves and just having them milled.
Which brings me back to my original point that buying 5.3 heads for an increase in power is pointless when you already have ls1 heads. Period.
Now, I'm not trying to rudely correct you, however, I do know what I am talking about.
As far as my other posts, they will stay. The ports on the 5.3 heads may be the same but with the stock valve sizing of the 5.3 heads, they will not flow the same. Velocity may be a tad higher given the smaller valve and given the same volume of the cylinder, but putting a stock 5.3 head up against a stock ls1 head and claiming 10 HP from .6 increase in compression ratio is nonsense. If that was the case, everyone would have stock 5.3 heads on their cars.
After the installation of the larger valves in the 5.3 head, you basically have a stock milled ls1 head.
Call any machine shop and compare prices to install larger valves and just having them milled.
Which brings me back to my original point that buying 5.3 heads for an increase in power is pointless when you already have ls1 heads. Period.
Now, I'm not trying to rudely correct you, however, I do know what I am talking about.
Your going to end up spending a little less on the 5.3 heads along with a vj to make a little more power than a LS1 head with a valve job. If you already have the 5.3 heads its a no brainer.
01-27-2012, 02:15 AM
#57
Agreed, but the op already stated he has ls1 heads, so wouldn't it make more sense to go with what you already have?
I think so.
Also, one other thing, once you un shroud the intake valve, your going to add some cc's back to the chamber. So you won't gain as much compression as you would with a stock chamber.
Once all said and done, after all the work the 5.3 head requires to bring it on par with the ls1 head in the same configuration, it's a wash. If you can't agree to that then all hope is lost trying to make you see that.
Even if the 5.3 heads flow marginally more than the ls1 head after all is said and done, you won't notice it once it is on the car and running.
Also, even if I had 5.3 heads, I would sell them and pick up some ls1 heads. Because according to you, they are the same price. And being that milling is cheaper process than adding larger valves, it's a no brainer...
At this point, I'm agreeing to disagree.
No hard feelings or bad blood, 6 in one half a dozen the other.
I think so.
Also, one other thing, once you un shroud the intake valve, your going to add some cc's back to the chamber. So you won't gain as much compression as you would with a stock chamber.
Once all said and done, after all the work the 5.3 head requires to bring it on par with the ls1 head in the same configuration, it's a wash. If you can't agree to that then all hope is lost trying to make you see that.
Even if the 5.3 heads flow marginally more than the ls1 head after all is said and done, you won't notice it once it is on the car and running.
Also, even if I had 5.3 heads, I would sell them and pick up some ls1 heads. Because according to you, they are the same price. And being that milling is cheaper process than adding larger valves, it's a no brainer...
At this point, I'm agreeing to disagree.
No hard feelings or bad blood, 6 in one half a dozen the other.
01-27-2012, 02:25 AM
#58
TECH Senior Member
iTrader: (96)
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 24,240
Likes: 0
Received 81 Likes
on
72 Posts
The 5.3 heads are dirt cheap. Valve jobs are cheap. If they flow almost identical with the 5.3 heads having a smaller valve, a larger valve will certainly bring them in line or above the 241's/853's. Add in the added compression and it's a no brainer that they will make more power, and make the engine more responsive throughout the rev range due to the rise in CR.
Your going to end up spending a little less on the 5.3 heads along with a vj to make a little more power than a LS1 head with a valve job. If you already have the 5.3 heads its a no brainer.
Your going to end up spending a little less on the 5.3 heads along with a vj to make a little more power than a LS1 head with a valve job. If you already have the 5.3 heads its a no brainer.
01-28-2012, 01:55 PM
#59
On The Tree
Join Date: Oct 2011
Location: Dirty South
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
I am thinking of building a set of heads using 5.3 castings. These would be hand ported and receive a valve job to accommodate a larger 2.00 ls1 intake valve.
Why 5.3? For the compression boost and the fact that they are cheap.
Thanks to everyone's input I now know that the 2.00 valve swap is possible after a valve job, the seat does not need to be replaced. Now I am trying to find out if further work is needed to make this work. I am concerned about the issues with shrouding that chrisfrost and bww3588 mentioned earlier in the thread. Is this going to be a problem? What would need to be done to correct it? Thanks.
